539 research outputs found

    High Reclaimed Asphalt Pavement in hot mix asphalt

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    When old roads have to be replaced, the existing pavement, known as Reclaimed Asphalt Pavement (RAP) is ripped up, milled, and stockpiled and can be used in the creation of new mixes in order to save money and resources. New Jersey state specifications limit the percentage of RAP that can be used to 15% for surface courses and 25% for the intermediate and base courses; however, other states have implemented much higher RAP percentages. The limitations are placed because the interaction between the virgin and residual RAP binder is unknown, with respect to the amount of residual binder that is active in the mix and the effect that this blended binder will have on performance since aged binder has a tendency to be stiffer. In this report, the methods and findings are explained for low temperature laboratory performance of asphalt mixes with 25% and 35% RAP as well as a control mix and RAP samples from Delaware. In addition to this, a coating study, blending study, variability study, and cost analysis were performed and the use of blending charts was investigated. The Superpave Mix Design Excel Spreadsheet was also modified to account for degree of blending. The final section of the report provides recommendations for the use of RAP in New Jersey

    Pupil and teacher perceptions of the taxonomic classification of Senior Certificate Mathematics Higher Grade examination questions

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    Bibliography: page 59.This dissertation seeks to apply a taxonomic classification to Senior Certificate Mathematics examination questions. Candidates who wrote a typical question paper as well as the teachers who taught them were asked to give their taxonomic perceptions of each question. The taxonomic classifications of both pupils and teachers are compared. The effect of the ability of pupils in the subject on their classifications is considered and a relationship between performance score and pupil classification is shown to exist

    An Analysis of First-Year Registration at WPI

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    This report is an analysis of student interactions with the course registration system at WPI with a focus on the waitlist process. We identified student ignorance, poor communication, and a lack of personal responsibility as three related causes for unnecessary waitlists and student frustration. Simple intervention such as peer advising and a scheduling tool, were able to help first year students, and reduce the number on waitlists by 50% for this group

    Self-management Interventions for Pain and Physical Symptoms Among People Living With HIV:A Systematic Review of the Evidence

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    Introduction: Pain and symptoms still persist among people living with HIV/AIDS. Evidence-based self-management interventions have the potential to help people with HIV/AIDS to successfully manage pain and symptoms. We aimed to identify and appraise the evidence regarding the effectiveness of self-management interventions for pain and/or physical symptoms in people living with HIV/AIDS. Methods: We searched for controlled intervention studies in Amed, Assian, CINAHL, Cochrane Library, Embase, Medline, PsycInfo, Scopus, and Web of Science data bases, from 1984 to February 2017. Two reviewers screened and extracted data, assessed risk of bias (using Joanna Briggs Institute Critical Appraisal checklist for randomized and nonrandomized trials), and rated the quality of evidence (GRADE tool). Results: We identified 22 original papers reporting 19 different studies. Of these, 17 used randomized controlled trial designs. Three studies reported data on pain severity, and 2 studies reported data on pain interference outcomes with one study reporting positive effect on both outcomes. Outcomes for physical symptoms were reported in 13 studies with 6 studies reporting positive effect. The quality of evidence was moderate for pain outcomes. For physical symptoms, one study was rated as moderate; the rest were rated as low n = 8 and very low n = 4 quality. Conclusions: There is some evidence to suggest that self-management interventions delivered either online, face-to-face, or group-based consisting of booklet, leaflet, or manuals are effective in improving pain and physical symptoms. Findings suggest the need for theoretically plausible high-quality clinical trials of pain and physical symptom self-management among culturally diverse people with HIV

    Evaluation of gellan gum fluid gels as modified release oral liquids

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    Oral liquids are often preferred for drug administration to patients for whom swallowing is difficult, however formulating modified release versions can be challenging. A potential route to achieve modified release in oral liquids is by using fluid (sheared) gels formed by introducing a shear field during gelation in gel-forming biopolymers. These fluid gels can act as pourable viscoelastic fluids but retain true gel micro/nano structure. Here, we have demonstrated that fluid gels have potential as paediatric oral liquids preventing release of ibuprofen in simulated gastric fluid. Subsequent release at pH 7.4 was affected by the duration of exposure and magnitude of acid pH with a linear relationship between onset of release and the preceding acidic exposure duration. Delayed release was a result of increasing gel stiffness, a consequence of the acidity of the initial release media and exposure time. A much faster release rate was measured when exposure time in acid was 10 min compared with 60 min. This study highlights the potential to design fluid gels that are tuned to have a specified stiffness at a particular pH and exposure time. This could enable the preparation oral liquids with modified release behaviour

    Light scattering corrections to linear dichroism spectroscopy for liposomes in shear flow using calcein fluorescence and modified Rayleigh-Gans-Debye-Mie scattering

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    The interpretation of data from absorbance spectroscopy experiments of liposomes in flow systems is often complicated by the fact that there is currently no easy way to account for scattering artefacts. This has proved particularly problematic for linear dichroism (LD) spectroscopy, which may be used to determine binding modes of small molecules, peptides and proteins to liposomes if we can extract the absorbance signal from the combined absorbance/scattering experiment. Equations for a modified Rayleigh-Gans-Debye (RGD) approximation to the turbidity (scattering) LD spectrum are available in the literature though have not been implemented. This review summarises the literature and shows how it can be implemented. The implementation proceeds by first determining volume loss that occurs when a spherical liposome is subjected to flow. Calcein fluorescence can be used for this purpose since at high concentrations (> 60 mM) it has low intensity fluorescence with maxima at 525 and 563 nm whereas at low concentrations (<1 mM) the fluorescence intensity is enhanced and the band shifts to 536 nm. The scattering calculation process yields the average axis ratios of the distorted liposome ellipsoids and extent of orientation of the liposomes in flow. The scattering calculations require methods to estimate liposome integrity, volume loss, and orientation when subjected to shear stresses under flow

    Algae–P relationships, thresholds, and frequency distributions guide nutrient criterion development

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    Abstract. We used complementary information collected using different conceptual approaches to develop recommendations for a stream nutrient criterion based on responses of algal assemblages to anthropogenic P enrichment. Benthic algal attributes, water chemistry, physical habitat, and human activities in watersheds were measured in streams of the Mid-Atlantic Highlands region as part of the Environmental Monitoring and Assessment Program of the US Environmental Protection Agency. Diatom species composition differed greatly between low-and high-pH reference streams; therefore, analyses for criterion development were limited to a subset of 149 well-buffered streams to control for natural variability among streams caused by pH. Regression models showed that TP concentrations were ;10 lg/L in streams with low levels of human activities in watersheds and that TP increased with % agriculture and urban land uses in watersheds. The 75 th percentile at reference sites was 12 lg TP/L. Chlorophyll a and ash-free dry mass increased and acid and alkaline phosphatase activities decreased with increasing TP concentration. The number of diatom taxa, evenness, proportion of expected native taxa, and number of high-P taxa increased with TP concentration in streams. In contrast, the number of low-P native taxa and % low-P individuals decreased with increasing TP. Lowess regression and regression tree analysis indicated nonlinear relationships for many diversity indices and attributes of taxonomic composition with respect to TP. Thresholds in these responses occurred between 10 and 20 lg/L and helped justify recommending a P criterion between 10 and 12 lg TP/L to protect highquality biological conditions in streams of the Mid-Atlantic Highlands

    Convection forced by a descending dry layer and low-level moist convergence

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    This is the post-print version of the Article - Copyright @ 2009 Wiley-BlackwellA narrow line of convective showers was observed over southern England on 18 July 2005 during the Convective Storm Initiation Project (CSIP). The showers formed behind a cold front (CF), beneath two apparently descending dry layers (i.e. sloping so that they descended relative to the instruments observing them). The lowermost dry layer was associated with a tropopause fold from a depression, which formed 2 d earlier from a breaking Rossby wave, located northwest of the UK. The uppermost dry layer had fragmented from the original streamer due to rotation around the depression (This rotation was also responsible for the observations of apparent descent—ascent would otherwise be seen behind a CF). The lowermost dry layer descended over the UK and overran higher θw air beneath it, resulting in potential instability. Combined with a surface convergence line (which triggered the convection but had less impact on the convective available potential energy than the potential instability), convection was forced up to 5.5 km where the uppermost dry layer capped it. The period when convection was possible was very short, thus explaining the narrowness of the shower band. Convective Storm Initiation Project observations and model data are presented to illustrate the unique processes in this case.This work is partly funded by the Natural Environment Research Council (NERC)
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